Extraction sleeve for drill rods



April 1962 c. B. EBERMAN ET AL 3,029,099

EXTRACTION SLEEVE FOR DRILL RODS Filed April 25, 1960 nite rates atent EXTRACTKUN LEEVE FQR DRILL RODS Carl Biirje Eben-man and Karl Stine Snndstcdt, Sandviken,

Sweden, assignors to Sandvikens Jernverlrs Alitieholag, Sandvilren, Sweden, a corporation of Sweden Filed Apr. 25, 1960, Ser. No. 24,532 Claims priority, application Sweden Apr. 24, 1959 6 Claims. (Cl. 294-402) The present invention relates to extraction sleeves for drill rods and other parts of drilling equipment which inadvertently may be lost in drill holes. For instance in percussion drilling the drill rod or an associated part such as a jointing or connecting sleeve may be lost due to breakage or inadvertently dropped into a vertical hole.

Herctofore conical extraction sleeves have been used in the recovery of such lost parts the sleeve being forced downwardly upon the lost part and the conical surface thereof engaging the lost part with sufficient friction to permit it to be lifted out of the hole. Such conical sleeves have not however proven to be entirely satisfactory due to the relatively weak connection between the sleeve and the lost part.

It has been proposed also to provide a cylindrical extraction sleeve with longitudinal slots, the portions of the sleeve between the slots thus constituting flexible and resilient gripping lugs or fingers. Such sleevm also sufier from the defect that the gripping power thereof is relatively weak.

It has further been proposed to provide an extraction sleeve having a cylindrical opening, longitudinal slots which divide the sleeve into fingers, a conical outer surface and a cylindrical tube adapted to be forced down over said conical surface and to thus force the fingers inwardly to engage the lost object. This device is effective but somewhat complex and expensive.

An object of the present invention is to provide an extraction sleeve which is relatively simple and inexpensive but which has good gripping properties. The present invention takes into account the fact that lost parts to be recovered have different shapes and provides differently shaped sleeves adapted to function with such differently shaped lost parts. An object of the invention is to provide a sleeve which has a cross-sectional shape which is different from that of the lost object. In use, such a sleeve is forced over the lost part and is thus distorted to some extent so that its cross-section tends to assume the cross-sectional shape of the lost object. Thus the side wall of the sleeve, being bent and somewhat resilient, tends to firmly grip the lost object so that it can be lifted, with the sleeve, out of the drill hole.

The extraction sleeve may be mounted as usual at the end of the drill rod connection and may be forced upon, i.e. engaged with, the lost object by the action of the drilling equipment which normally operates the drill rod. Thus very few extra parts are required. Extraction sleeves of the kind described above have proven to be highly efiicient.

The invention is illustrated in the accompanying drawings in which FIG. 1 is a longitudinal section view in a plane indicated by the line 1l of FIG. 4, of an extraction sleeve in accordance with the present invention;

FIG. 2 is a front view of a modified shape of sleeve corresponding to the cross-section shown in FIG. 6;

FIGS. 3-7 illustrate various sleeve cross sectional shapes, FIGS. 3, 4 and 5 being cross-sections of sleeves in the vicinity of the line A-A of FIG. 1 and FIGS. 6 and 7 being cross-sections of sleeves in the vicinity of the line BB of FIG. 2.

When a break has occurred in a drill hole, generally it is the drill bit or a joining sleeve that is lost. Since the 3,ll29,99 Patented Apr. 10, 1962 broken drill bit generally presents an edge or angular end whereas the joining sleeve generally presents a circular end and is larger than the drill bit end, different extracting tools, that is extracting tools presenting differently shaped gripping parts are required.

Referring tothe drawings, the extraction sleeve illustrated in FIG. 1 comprises the hollow, cylindrical attaching part 11 adapted to be attached to the rod, wire or the like of the conventional drilling apparatus. Conveniently it may be attached to the same joining rod which is normally used for attachment to the drill bit and is provided with internal threads 12 for this purpose. It will be appreciated however the attaching part of the extraction sleeve may have other forms, for instance a conical socket adapted to be attached to the conical end of a connecting rod.

The gripping part 13 of the extraction sleeve may be and preferably is integral with the attaching part 11. The part 13 also is tubular and its inner surface 15 has a uniform cross section up to its junction with the smaller end of the conical surface :17 in the entering part 16.

In the modification illustrated in FIG. 2, the attaching part 24 which also is tubular and may be provided with attaching threads (not shown) as in FIG. 1, is further shown as being provided with wrench grips 27 to facilitate its attachment to and detachment from a pull rod. The gripping part 26 of this modification is square in cross section as shown in FIG. 6 and is of uniform cross-section as in the modification shown in PEG. 1. The gripping part 26 of the modification of FIG. 2 is connected to or integral with the flared frusto conical or pyramidal entering part 25.

The different cross sectional shapes illustrated in FIGS. 3 to 7 are designed for gripping differently shaped objects. In case the object is angular in cross section the gripping part of the extraction sleeve or tool may be circular in cross-section as shown in FIG. 3. On the other hand if the object to be extracted is circular in cross-section it is preferable to use an extraction sleeve of non-circular cross section as shown in FIGS. 4-7.

In the modification shown in FIG. 4 the inner surface of the gripping part comprises the three portions 14- of the same cylindrical surface separated by the recesses 19 which, as shown, are cylindrical surfaces having a radius different from that of the portions 14. Obviously recesses of other cross sectional shapes e.g. angular, may be substituted for the cylindrical recesses 19.

In the modification shown in FIG. 5 the: inner surface of the gripping part is made up of four separated portions 2i) of the same cylindrical surface separated by inwardly extending cylindrical ridges 21. in this case as in the modification of FIG. 4 the surfaces 14 and l? and the surfaces 20 and 21 extend straight and parallel to the axis of the sleeve.

The modifications shown in FIGS. 6 and 7 are square and hexagonal respectively in cross-section and are made up of plane surfaces 23 connected to each other at rounded corners 22.

Referring to FIG. 1 the part 18 is a release area sepa rating the threads 12 from the gripping part 13.

As stated above the attaching part and the gripping part preferably are integral but may consist of two or more pieces connected together as by welding or shrinking. The outer diameters of the parts 11 and 13 may be the same or different as appears from FIGS. 1 and 2. Generally the gripping part has an uninterrupted wall as il1ustrated. The length of the gripping part 14 or 2-6 which is of uniform cross section should be at least and preferably at least of the sum of the lengths of the gripping part and the entering part.

As stated the extraction sleeves are designed and adapted for use in drilling and more particularly in percussive deep well drilling but it is apparent that the sleeves may be used in other similar situations in which objects such as drill tools are lost in inaccessible positions.

The invention is defined in the appended claims.

We claim:

1. An extraction sleeve comprising a. substantially cylindrical attaching part adapted to be connected at one end thereof to means for manipulating said sleeve, a gripping part which is tubular and coaxial with and has one end. thereof connected to the other end of said attaching part, and an entering part connected end to end with the other end of saidgripping part, said entering part having an outwardly flared inner surface the smaller end of which is of the same size and shape as the adjacent end of the inner surface of said gripping part and said gripping part having an imperforate Wall which is resilient and deformable under the conditions of gripping use and is of uniform internal cross section; the length of said gripping part being at least equal to the length of the entering part.

2. An extraction sleeve as defined in claim 1 in which the cross section of the internal surface of said gripping part is circular.

3. An extraction sleeve as defined in claim 1 in which.

the cross section of the internal surface of said gripping part is polygonal.

4. An extraction sleeve as defined in claim 1 in which the inner surface of said gripping part comprises parallel portions of'the same cylindrical surface separated by outwardly extending grooves.

5. An extraction sleeve as defined in claim 1 in which the inner surface of said gripping part comprises parallel sections of the same cylindrical surface separated by inwardly extending ridges.

6. An extraction sleeve as defined in claim 1 in which the cross section of the internal surface of said gripping part is square.

References Cited in the file of this patent UNITED STATES PATENTS 995,143 Horn June 13, 1911 1,051,225 Heeter Ian. 21, 1913 1,793,105 Lidderdale Feb. 17, 1931 2,601,351 Wilburn Jan. 24, 1952 2,653,840 Bitzer et al Sept. 29, 1953 2,709,907 Robertson et a1. June 7, 1955 2,848,268 McAuliffe Aug. 19, 1958 

